1. Field of the Invention
This invention relates to rolling machines and, more particularly, to controlled deflection rolls comprising an inner nonrotative shaft having a roll shell journaled about it, the inner shaft being automatically and controllably bent in an opposed manner to insure straightness of the outer roll shell.
2. Description of the Prior Art
Roll pressing mechanisms generally employ parallel rolls positioned to form pressure nips for rolling materials between them which causes a deflection of the rolls due to forces at the nip, and due to natural forces within the rolls themselves. Other mechanisms employ rolls that are subject to deflection forces, such as those carrying a traveling belt or web. In press roll couples, and in other roll arrangements wherein a pair of rolls are in a nip defining relationship with one another, the algebraic summation of the weight, the nip forces, and the bending movements produced by the journal loading, tend to produce in each of such rolls a curvature of its centroidal axis, in accordance with known laws governing the flexure of materials under strain.
A variety of arrangements have been devised to reduce the effect of such deflection within the roll. U.S. Pat. No. 3,587,152, assigned to the assignee of the present invention, discloses a hydrostatic bearing arrangement on a nonrotative shaft having a roll shell journaled about it. The hydrostatic bearings which deflect the nonrotating shaft have the capability within limits to transmit forces between the surface of a hydrostatic plunger portion of the bearing and the inner roll shell, even if the surfaces are not axially aligned due to deflection of the inner shaft. U.S. Pat. No. 3,443,295 shows a table roll having an inner shaft that has bolts on ends of the shaft which may be manually turned inwardly to cause the shaft ends to deflect downwardly, thereby creating an upward bend across the middle of the shaft.
Another arrangement for controlling deflection is described in U.S. Pat. No. 3,802,044, which discloses a roll journaled about a shaft, the shaft having tiltable pistons for compensating against any deviation in position between the shaft and the roll shell.
Further art is found in U.S. Pat. Nos. 3,869,774; 3,731,357; 3,416,435 and 3,119,324. Some of these prior art devices are unduly complicated and none utilizes the combination and general functioning of hydrostatic bearings with counter bending of nonrotative shafts in an automatic and controlled manner, as described in the present invention.